The U.S. opposition to the Islamic State (a jihadi army formerly known as ISIS) finally came to a head last night after President Barack Obama ordered a series of air strikes against the group’s positions near Erbil in the Kurdish-controlled area of northern Iraq. The goal of this limited bombing campaign appears to be relieving Kurdish troops, helping the Yazidis, a besieged group of religious minorities, and protecting American citizens currently in Erbil.The air strikes marked the first time the U.S. had taken direct action against ISIS, a hard-line Islamist movement that stretches back roughly a decade. Led by a charismatic former member of Al Qaeda named Abu Bakr al-Baghdadi, the group has long been part of the rebels fighting against Syrian President Bashar al-Assad. More recently, ISIS militants have taken over parts of northern and western Iraq and advanced to as close as 12 miles outside Baghdad, the Iraqi capital. In the process, ISIS has killed thousands and implemented a brutal form of medieval-style justice.

An Islamist fighter films his fellow militants on June 30 as they march in a parade along the streets of Syria's northern Raqqa province.REUTERSAs ISIS has grown, Vocativ has followed it on the deep web, tracking its movements, its recruitment process, the people who stand against its fighters and the supporters who buy its gear. Here’s a closer look at America’s latest target.COULD SAUDI ARABIA BE THE NEXT ISIS CONQUEST?ISIS: WE ARE OPERATING IN GAZATRACKSUITS AND TRICYCLES: THE WEIRD WORLD OF ISIS-BRANDED MERCHANDISEISIS TRIES TO OUTWIT SOCIAL NETWORKSDID “SUPERPOWER” TURKEY UNDERESTIMATE ISIS?ISIS SEIZES U.S. WEAPONS IN IRAQKNIGHTS OF ANGER: BAGHDAD’S MILITIAS ARE READY FOR WAR WITH ISISCLAIMS OF DEATH, TORTURE AND ABUSE INSIDE ISIS PRISONSGUN-TOTING TODDLER AN ISIS PROPAGANDA ICONISIS TO FIFA: CANCEL THE WORLD CUP OR WE’LL BOMB ITKUWAITIS WORRY THAT THEY’RE NEXT IN LINE FOR AN ISIS INVASIONISIS IS LITERALLY CRUCIFYING ITS ENEMIESCOULD BITCOIN FUND ISIS FIGHTERS?ONE ISIS RECRUIT’S JOURNEY, AS TOLD THROUGH HIS FACEBOOK PAGENOW AVAILABLE IN THE ANDROID STORE: AN APP FOR TERRORISTSTHE MIDDLE EAST’S NEWEST KINGMAKERS FIGHT ISISMEET THE 75-YEAR-OLD JIHADI GRANDFATHERI’VE BEEN A JIHADI FOR 40 YEARSCAN THESE REGULAR DUDES DEFEND BAGHDAD FROM ISIS?EXCLUSIVE: CONVERSATIONS WITH A SELF-PROFESSED JIHADI